Re: Parser for cmd language?

[Dan Kegel]

On Thu, Dec 17, 2009 at 3:05 AM, Henri Verbeet  wrote:
> > If it's not ok to require Java to build (and I could imagine that),
> > we could check in ANTLR's output.  Then only people
> > hacking on cmd would need java installed.
>
> Well, at least Alexandre as well, and I could imagine distributions
> wanting to generate those files themselves as well.

Sure.  And they can do 'apt-get install antlr3' or the equivalent pretty easily.
> IIRC ANTLR also includes its own IDE/editor, although it's probably
> not required to use that.

You certainly don't need to use any ide.
> It seems to me like it would be less trouble
> to either use bison/yacc or write something by hand,  like most of the
> other parsers in Wine. The more interesting problem is of course
> finding someone to work on it in the first place.

The two problems are not unrelated.  It's possible that
finding somebody willing to use antlr would be easier
than finding somebody willing to use yacc or write it
from scratch.

I'm also biased towards hand-written parsers, but the
cmd language is big and hairy; it's tempting to try
prototyping the parser with antlr before diving in
to write it by hand.  And who knows, maybe the antlr
version would suffice.

I'm trying to build "hello, antlr" now as a reality check.
... ok.  Here's what I had to do for a java example on jaunty:

Copy and paste the grammar and test program from
http://www.antlr.org/wiki/display/ANTLR3/Expression+evaluator
into Expr.g and Test.java

sudo apt-get install antlr3
antlr3 Expr.g
javac -cp .:/usr/share/java/antlr3-3.0.1+dfsg.jar Test.java
ExprLexer.java ExprParser.java

It originally gave me the error
ExprParser.java:163: warning: [unchecked] unchecked call to put(K,V)
as a member of the raw type java.util.HashMap
                    memory.put(ID2.getText(), new Integer(expr3));
                              ^
but that just meant the example is for old java; I had to update the line
HashMap memory = new HashMap();
to
HashMap<String,Integer> memory = new HashMap<String,Integer>();

Then all went tickety-boo, no gui involved, and the demo worked.

Now to try the same thing in C.  But sleep first.